Induction of secondary dormancy in rape seeds (Brassica napus L.) by prolonged imbibition under conditions of water stress or oxygen deficiency in darkness

AbstractThis study investigated the induction and loss of dormancy in oilseed rape (Brassica napus). Twenty genotypes were preliminary screened; from these, two genotypes, RGS003 and Hayola 308, which possess high potential for dormancy induction (HSD) and medium potential to induce secondary dormancy (MSD), were selected. The stratification of seeds at alternating temperatures of 5–30°C (in dark) significantly relieved secondary dormancy, but dormancy was not fully released. The ψb(50) values were −1.05 and −1.06 MPa for the MSD and the HSD before dormancy induction. After inducing dormancy, the ψb(50) values for the MSD and the HSD were increased to −0.59 and −0.01 on day 0 stratification at 20°C. The hydrothermal time (θHT) value was low for one-day stratification for HSD in comparison with other stratification treatments. Water stress can induce dormancy (if the seeds have the genetic potential for secondary dormancy) and warm stratification (in dark) can only reduce the intensity of dormancy. The seeds with a high potential of dormancy induction can overcome dormancy at alternating temperatures and in the presence of light. It can, therefore, be concluded that a portion of seeds can enter the cycle of dormancy ↔ non-dormancy. The secondary dormant seeds of B. napus cannot become non-dormant in darkness, but the level of dormancy may change from maximum (after water stress) to minimum (after warm stratification). It seems that the dormancy imposed by the conditions of deep burial (darkness in combination with water stress and more constant temperatures) might be more important to seed persistence than secondary dormancy induction and release. The dormancy cycle is an important pre-requisite in order to sense the depth of burial and the best time for seed germination.

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Fullerol improves seed germination, biomass accumulation, photosynthesis and antioxidant system in Brassica napus L. under water stress

Plant Physiology and Biochemistry ◽

10.1016/j.plaphy.2018.05.026 ◽

2018 ◽

Vol 129 ◽

pp. 130-140 ◽

Cited By ~ 17

Author(s):

Jun-Lan Xiong ◽

Jun Li ◽

Hang-Chao Wang ◽

Chun-Lei Zhang ◽

Muhammad Shahbaz Naeem

Keyword(s):

Water Stress ◽

Brassica Napus ◽

Seed Germination ◽

Antioxidant System ◽

Biomass Accumulation ◽

Brassica Napus L

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Classification of canola (Brassica napus) winter cultivars by secondary dormancy

Canadian Journal of Plant Science ◽

10.4141/cjps08190 ◽

2009 ◽

Vol 89 (4) ◽

pp. 613-619 ◽

Cited By ~ 18

Author(s):

S Gruber ◽

K Emrich ◽

W Claupein

Keyword(s):

Cluster Analysis ◽

Brassica Napus ◽

Environmental Factors ◽

Seed Bank ◽

Soil Seed Bank ◽

Canola Seed ◽

Brassica Napus L ◽

Secondary Dormancy ◽

Specific Trait

Secondary dormancy is the major reason for seed persistence of canola (Brassica napus L.) in the soil. Volunteers emerging from the soil seed bank can lead to unwanted gene dispersal. More than 40 B. napus canola cultivars were tested for secondary dormancy under laboratory conditions. All cultivars were classified into groups of low, medium, and high dormancy by performing a cluster analysis. The results suggest that secondary dormancy is a cultivar-specific trait. Additionally, inter-year variation in dormancy indicates that it seems to be influenced by a set of environmental factors. Among years, classification of cultivars based on relative rank was more robust than classification based on absolute dormancy values. The classification of cultivars by their dormancy level would allow farmers to select and grow low-dormancy cultivars. Knowledge about the relative secondary dormancy of the currently grown cultivars could help growers and breeders lower canola seed bank persistence. Key words: Brassica napus, cluster analysis, genotype, secondary dormancy, soil seed bank

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